Water Loss

[Steve940estate]

Oh I see, the Green is the new one. Yes I think my one is grey thought it was black for some reason.
There aren't any signs of leaks around the cap if that is the problem.

Thanks for the replies.

[Crispy-d]

I haven't seen any water in the footwells and the heating works well, but that's my car! My friend's 940 emptied all its coolant into the passenger footwell, it was quite noticeable! But I've heard failing heater matrices is a common problem. Would be nice to find out as it's very annoying and also worrying. Hope it all works out.

[Steve940estate]

I have been keeping a check on the water level and I'm now pretty certain that its the head gasket that has failed.
Because of the position of the leak I don't think water is getting into the combustion chambers yet so it might be ok for a while until I get the chance to change it.
There is still a slim chance it couild be the seal on the water pump to head gasket but the water stain looks too far back.

Is this a common area for the gasket to fail (No 1 cyclinder by the water pump) or has my car done something odd ?

[CTCNetwork]

Hi,

Originally Posted by Crispy-d

I have disappearing coolant in my S90, but can't see any obvious leaks. And there is no contamination in either the expansion tank or the oil filler. It uses quite a bit more when I drive it hard. It's booked in for a nice big service, everything's being flushed and changed, including all belts and pulleys etc. I'll ask for the water pump to be done as well and for him to look for a leak. But it runs flawlessly otherwise, so I can't believe (well, don't want to believe) it's the gasket - I gather it's a nasty job.

You run your aircon all the time?
That will remove any condensation in the car which may tell you have a problem with the heater matrix..

Des. . .

[Clan]

Originally Posted by Steve940estate

I have been keeping a check on the water level and I'm now pretty certain that its the head gasket that has failed.
Because of the position of the leak I don't think water is getting into the combustion chambers yet so it might be ok for a while until I get the chance to change it.
There is still a slim chance it couild be the seal on the water pump to head gasket but the water stain looks too far back.

Is this a common area for the gasket to fail (No 1 cyclinder by the water pump) or has my car done something odd ?

It is far more likely that the waterpump top seal ring had gone hard over the years , it is an easy job to change i'd do that first . The small weep will be blowing back along the head gasket joint as the leak will be at the same level . dont forget the heater return seal into the water pump too .

[Steve940estate]

Thanks for the info Clan, I will get a mirror or wedge my head in the gap for a better look.

The car hasn't done a very high mileage and hasn't had much done to it so I expect the seal is the original, I have my fingers crossed !

[Clan]

940 head gaskets are not prone to failing as a rule so Good Luck !

[Steve940estate]

Just to update this thread it was the head gasket.

I took the water pump off and checked the seal and it looked ok. With the water pump and a few other bits out of the way I could see that the head gasket didn't look to good so thought I might as well take the head off as I had already drained the coolant.

With the head off it was clear it wouldn't have lasted much longer. There is a waterway at the front that is very near to the outside of the block and the gasket was gradually giving up.

I have re-fitted the head now with a new gasket and will hopefully finish it off tomorrow. My only worry is that there was a bit of corrosion where the water had been getting out, I just hope after cleaning it up carefully it will seal ok.

[CTCNetwork]

Hi,

The "judicious" application of the sealant used for sealing 2 part heads where you had your leak (after maybe a light rub with very fine wet&dry or wire wool) could be a solution to that.

Best though would be a very light skim of the block and maybe head (only if needed) would solve any corrosion issue.
You'll know what to do next time and have the time to arrange things to do it..

Des. . .

[Crispy-d]

Originally Posted by CTCNetwork

Hi,

You run your aircon all the time?
That will remove any condensation in the car which may tell you have a problem with the heater matrix..

Des. . .

Hello Des - thanks for the input.

Well I don't use the aircon that much. Unless it's really hot, I just drive around with the windows open; the fan is usually set to 0 and the temperature to the coldest setting. I have noticed that it steams up really badly, especially at night, and that's when I use the demister which automatically turns on the aircon. If it's steaming up when I have the windows shut and it's cold outside could that mean heater matrix then? I was expecting to see pools of water in the footwell if that was the case!

Crispin

P.S. I forgot to mention that mine has an undertray which doesn't help when trying to look underneath on the driveway, but looking from the top I can see a wet patch on the tray directly under the engine. I can't see exactly where it's coming from, neither can I see any drips with the engine running. Of course I still don't know if that's just condensation from the aircon - I must check after doing a journey with the aircon off!